1997550 has 72 divisors (see below), whose sum is σ = 5629104. Its totient is φ = 506880.

The previous prime is 1997543. The next prime is 1997557. The reversal of 1997550 is 557991.

It is a happy number.

1997550 is a `hidden beast` number, since 19 + 97 + 550 = 666.

It is an interprime number because it is at equal distance from previous prime (1997543) and next prime (1997557).

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1997557) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 10254 + ... + 10446.

It is an arithmetic number, because the mean of its divisors is an integer number (78182).

2^1997550 is an apocalyptic number.

1997550 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 1997550, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2814552).

1997550 is an abundant number, since it is smaller than the sum of its proper divisors (3631554).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1997550 is a wasteful number, since it uses less digits than its factorization.

1997550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 234 (or 226 counting only the distinct ones).

The product of its (nonzero) digits is 14175, while the sum is 36.

The square root of 1997550 is about 1413.3470911280. The cubic root of 1997550 is about 125.9406371915.

The spelling of 1997550 in words is "one million, nine hundred ninety-seven thousand, five hundred fifty".